Method and apparatus for aligning a substrate on a stage

Abstract

A method for aligning a workpiece may include determining a first and second position of a first edge of the workpiece based on a first and a second position of a pickup device. The workpiece may be aligned based on the first and second position of the pickup device. The at least first and second positions of the pickup device may be determined based on an intersection of a laser beam and the workpiece.

1. A method for aligning a workpiece, the method comprising:
 detecting a first and second position of a first edge of the workpiece based on a first and a second position of a pickup device; and 
 aligning the workpiece based on the first and second positions of the pickup device; wherein
 the first and second positions of the pickup device are detected based on intersections of a laser beam and the workpiece, and 
 the detecting and aligning are performed during fetching of the workpiece by the pickup device. 
 
 
   
   
     2. The method of  claim 1 , wherein the detecting the first position further includes,
 fetching the workpiece, 
 moving the workpiece in a first direction toward the laser beam, and 
 registering the position of the pickup device when the first edge of the workpiece is at least partly breaking the laser beam. 
 
   
   
     3. The method of  claim 1 , wherein the detecting of the second position further includes,
 displacing the workpiece, 
 moving the workpiece in a direction toward the laser beam, 
 detecting with a detector when the second edge of the workpiece is at least partly breaking the laser beam, and 
 registering the position of the pickup device when the second edge of the workpiece is at least partly breaking the laser beam. 
 
   
   
     4. The method of  claim 1 , wherein the aligning of the workpiece further includes,
 computing an angle error of the workpiece based on the at least first second and third positions, 
 correcting the angle error of the workpiece, and 
 placing the workpiece onto a stage. 
 
   
   
     5. The method according to  claim 1 , wherein the workpiece is aligned in at least one of an x and y direction while being arranged on a stage. 
   
   
     6. The method according to  claim 5 , wherein the alignment of the workpiece in at least one of the x and y direction is performed by detecting a position of the workpiece using a camera and moving the workpiece into a position using the stage. 
   
   
     7. The method according to  claim 1 , wherein the positions of the first edge and the second edge are detected by detecting an edge using an edge detector, while the workpiece is supported by a stage and moving the workpiece into a position using the stage. 
   
   
     8. The method according to  claim 7 , wherein the edge detection is performed using a detector which is capable of detecting a change in property of a reflected laser beam when passing at least one of the first and second edges, while the workpiece is supported by the stage. 
   
   
     9. The method according to  claim 4 , wherein the stage is movable in at least one of an x and y direction. 
   
   
     10. A method for aligning a workpiece, the method comprising:
 detecting a first and second position of a first edge of the workpiece based on a first and a second position of a pickup device; 
 detecting a first position of a second edge of the workpiece based on a third position of the pickup device; and 
 aligning the workpiece based on the first, second, and third positions of the pickup device; wherein
 the first, second, and third positions of the pickup device are detected based on intersections of a laser beam and the workpiece, and 
 the first, second, and third positions of the pickup device are detected, and the aligning is performed, while the workpiece is fetched by the pickup device. 
 
 
   
   
     11. The method of  claim 10 , wherein the detecting the first position further includes,
 fetching the workpiece, 
 moving the workpiece in a first direction toward the laser beam, and 
 registering the position of the pickup device when the first edge of the workpiece is at least partly breaking the laser beam. 
 
   
   
     12. The method of  claim 10 , wherein the detecting of the second position further includes,
 displacing the workpiece, 
 moving the workpiece in a direction toward the laser beam, 
 detecting with a detector when the second edge of the workpiece is at least partly breaking the laser beam, and 
 registering the position of the pickup device when the second edge of the workpiece is at least partly breaking the laser beam. 
 
   
   
     13. The method of  claim 10 , wherein the detecting of the first position of the second edge further includes,
 rotating the workpiece; 
 moving the workpiece in a second direction toward the laser beam; 
 detecting with the detector when the first position of a second edge of the workpiece is at least partially intersecting the laser beam; 
 registering the position of the robotic arm when the first position of the second edge of the workpiece is at least partially breaking the laser beam. 
 
   
   
     14. The method of  claim 10 , wherein the aligning of the workpiece further includes,
 computing a position of the first edge; 
 correcting an angle error of the workpiece; 
 computing a position of the second edge; and 
 placing the workpiece onto a stage with the first and second edges are at positions. 
 
   
   
     15. The method of  claim 10 , wherein the laser beam has a wavelength does not affect material sensitive to electromagnetic radiation. 
   
   
     16. The method according to  claim 13 , wherein the workpiece is rotated 90°. 
   
   
     17. A method for aligning a workpiece, the method comprising:
 fetching the workpiece; 
 aligning the workpiece rotationally in a plane of a surface of the workpiece before arranging the workpiece on a stage; 
 arranging the workpiece on the stage; 
 aligning the workpiece in at least one of an x and y direction while being arranged on the stage. 
 
   
   
     18. The method according to  claim 17 , wherein the rotational alignment is performed by detecting two spaced apart positions on a common edge of the workpiece. 
   
   
     19. The method according to  claim 18 , further including,
 determining a position of another edge of the workpiece before arranging the workpiece on the stage. 
 
   
   
     20. The method according to  claim 17 , wherein the position of an edge of the workpiece is determined using an interferometer. 
   
   
     21. The method according to  claim 18 , wherein the position of the edge is determined using an interferometer. 
   
   
     22. The method according to  claim 17 , wherein the workpiece is at least partly covered with a layer sensitive to electromagnetic radiation and the stage is part of a pattern generator for patterning an arbitrary pattern onto the workpiece. 
   
   
     23. The method according to  claim 17 , wherein the position of an edge of the workpiece is determined using a detector capable of detecting a change in property of a reflected laser beam. 
   
   
     24. An apparatus for aligning a workpiece, the apparatus comprising:
 a laser adapted to irradiate the laser beam; 
 a detector for detecting when positions of at least one edge of the workpiece is at least partially intersecting the laser beam while the workpiece is fetched by a robotic arm, the robotic arm for moving the workpiece in at least one direction and placing the workpiece on a stage; and 
 a computer; wherein the computer is adapted to, 
 register positions of the robotic arm when the positions of the at least one edge of the workpiece at least partially intersect the laser beam, 
 compute an angle error of the workpiece based on registered positions of the robotic arm, 
 correct the angle error of the workpiece using the robotic arm, and 
 compute a position of the stage based on the registered positions of the robotic arm. 
 
   
   
     25. An apparatus for performing the method of  claim 1 . 
   
   
     26. An apparatus for performing the method of  claim 10 . 
   
   
     27. An apparatus for performing the method of  claim 17 . 
   
   
     28. A method for aligning a workpiece, the method comprising:
 determining a first and second position of a first edge of the workpiece based on a first and a second position of a pickup device; and 
 aligning the workpiece based on the first and second positions of the pickup device; wherein
 the first and second positions of the pickup device are determined based on intersections of a laser beam and the workpiece.